Display panel comprising a plurality of marks in at least one corner of substrate

ABSTRACT

A liquid crystal display panel includes an active matrix substrate, a counter substrate, a liquid crystal layer, and a sealant. The counter electrode is opposed to the active matrix substrate. The liquid crystal layer is provided between the active matrix substrate and the counter substrate. The sealant, which surrounds the liquid crystal layer between the active matrix substrate and the counter substrate, joins the active matrix substrate and the counter substrate and seals the liquid crystal layer. A portion of the surface on the liquid crystal layer side of the active matrix substrate which is located at the periphery of the liquid crystal display panel is flat.

BACKGROUND OF THE INVENTION

1. Summary of the Invention

The present invention relates to a display panel.

2. Description of the Related Art

A flat display panel typified by a liquid crystal display panel includesa pair of substrates of which peripheral portions are joined to eachother by means of a sealant and a display medium layer (for example, aliquid crystal layer) introduced in a cell formed by the pair ofsubstrates and the sealant. For manufacturing such a flat display panel,especially, for manufacturing a flat display panel comparatively smallin size, a method is employed, with a view to achieving high productionefficiency, in which a plurality of cells (constitutional units) areformed on a large-size mother glass substrate; scribe lines forindividually dividing the plurality of cells thus formed are formed;then the cells (constitutional units) are divided individually along thescribe lines (see Japanese Unexamined Patent Application Publication No.2003-222904 and Japanese Unexamined Patent Application Publication No.2004-212690, for example).

In the conventional scribing method as disclosed in Japanese UnexaminedPatent Application Publication No. 2003-222904 and Japanese UnexaminedPatent Application Publication No. 2004-212690, however, chips andcracks may be formed in the glass substrate which lowers the efficiencypercentage. In other words, the conventional flat display panel involvesinsufficient manufacturing efficiency (efficiency percentage).Particularly, recent progress in thinning the flat display panelaccompanies thinning of the glass substrates used, and therefore, a flatdisplay panel using such thin glass substrates (glass substrates havinga thickness of 0.5 mm or smaller or 0.4 mm or smaller, for example)makes the above problem more significant.

SUMMARY OF THE INVENTION

In order to overcome the problems described above, preferred embodimentsof the present invention provide a display panel that is capable ofbeing manufactured with high production efficiency.

A display panel in accordance with a preferred embodiment of the presentinvention includes: a first substrate; a second substrate opposed to thefirst substrate; a display medium layer provided between the firstsubstrate and the second substrate; and a sealant surrounding thedisplay medium layer between the first substrate and the secondsubstrate to join the first substrate and the second substrate andsealing the display medium layer. In the display panel in accordancewith the present preferred embodiment of the present invention, aportion of a surface on a display medium layer side of the firstsubstrate which is located at a periphery of the display panel is flat.It is preferable that each portion of the surfaces (the surface on thedisplay medium layer side and the surface on the opposite side of thedisplay medium layer side) of the first substrate which is located atthe periphery of the display panel is flat. More preferably, thesesurfaces are flat and smooth.

The first substrate may include a first substrate body and a flatteningfilm covering at least an entirety of the portion of the surface on thedisplay medium layer side of the first substrate body which is locatedat the periphery of the display panel. The flattening film may be aresin film. In the present specification, the term “resin film” means afilm containing organic resin or silicon resin. Further, the term“display medium layer” means a layer of which light transmittance orlight reflectance is modified by potential difference between electrodesopposed to each other or a layer spontaneously emitting light by currentflowing between the electrodes opposed to each other. Specifically, thedisplay medium layer includes, for example, liquid crystal layers,inorganic or organic electroluminescent layers, light emitting gaslayers, electrophoretic layers, electrochromic layers, and the like.Accordingly, the display panel in accordance with the present preferredembodiment of the present invention may be a liquid crystal displaypanel, an inorganic or organic electroluminescent display panel, or thelike.

Moreover, the term “flat” in the present specification means flat tosuch an extent that the micro variation amount of a surface is about 0.3μm or smaller, for example. The micro variation amount of a surface canbe measured by a probe type surface profiling device, P-15 manufacturedby KLA-Tencor Corporation.

The first substrate may be an active matrix substrate. Specifically, thefirst substrate further may include: a plurality of thin filmtransistors formed on the first substrate body; an interlayer insulatingfilm which is formed on the plurality of thin film transistors and inwhich a plurality of through holes open to the plurality of thin filmtransistors are formed; and a plurality of pixel electrodes which areformed on the interlayer insulating film and which are electricallyconnected to the thin film transistors through the plurality of throughholes. In this case, the interlayer insulating film is preferably formedas the flattening film on the entirety of the portion of the firstsubstrate body which is located at the periphery of the display panel.

In the display panel in accordance with a preferred embodiment of thepresent invention, preferably, a portion of a surface on a displaymedium layer side of the second substrate which is located at theperiphery of the display panel is flat. Preferably, each portion of boththe surfaces (the surface on the display medium layer side and thesurface on the opposite side of the display medium layer side) of thesecond substrate which is located at the periphery of the display panelis flat. More preferably, these surfaces are flat and smooth.

A display panel in accordance with another preferred embodiment of thepresent invention includes: a first substrate in which a plurality ofconductive members are provided; a second substrate opposed to the firstsubstrate; a display medium layer provided between the first substrateand the second substrate; and a sealant surrounding the display mediumlayer between the first substrate and the second substrate to join thefirst substrate and the second substrate and sealing the display mediumlayer. In the second display panel in accordance with the presentpreferred embodiment of the present invention, at least one scribe markis formed on a portion of the first substrate which is located at aperiphery of the display panel, the scribe mark being formed of the samefilm as a film forming the thinnest conductive member of all theplurality of conductive members. In the present specification, the term“conductive member” means a member presenting a conductivity of about10⁶ S/m or larger in the steady state. The conductivity may be measuredby a four-terminal method or the like.

In the display panel in accordance with the present preferred embodimentof the present invention, the first substrate may be an active matrixsubstrate. Specifically, the first substrate may include: a plurality ofgate lines extending in parallel to each other; a plurality of sourcelines extending in parallel to each other with an angle formed relativeto a direction that the plurality of gate lines extend; switchingelements connected to both the gate lines and the source lines; aninterlayer insulating film which is formed on the switching elements andin which a plurality of through holes open to the switching elements areformed; and a plurality of pixel electrodes electrically connected tothe switching elements through the plurality of interlayer insulatingfilms. In this case, the plurality of conductive members include theplurality of gate lines, the plurality of source lines, and theplurality of pixel electrodes. One or more scribe marks may be formed ofthe same film as a film forming the thinnest conductive member out ofthe plurality of gate lines, the plurality of source lines, and theplurality of pixel electrodes.

The plurality of pixel electrodes may be substantially made ofconductive oxide while the at least one scribe mark may preferably beformed of the same film as a film forming the plurality of pixelelectrodes. The conductive oxide includes indium thin oxide (ITO),indium zinc oxide (IZO), tin oxide (SnO), and the like, for example.

The at least one scribe mark may be substantially made of metal. Forexample, the at least one scribe mark may be formed of the same film asa film forming the electrode line.

Preferably, the at least one scribe mark may be separated from an edgeof the first substrate.

The at least one scribe mark may be in a polygonal form in plan viewhaving a side agreeing with an edge of the first substrate in plan view.In this case, preferably, the at least one scribe mark includes at leastone edge in perpendicular contact with an edge of the first substrate inplan view.

The at least one scribe mark may be substantially made of conductiveoxide.

These and other features, elements, steps, advantages, andcharacteristics of the present invention will be apparent from thefollowing description of preferred embodiments with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a liquid crystal display panel inaccordance with a preferred embodiment of the present invention.

FIG. 2 is a schematic sectional view of a portion taken along the lineII-II in FIG. 1

FIG. 3 is a partial sectional view of the liquid crystal display panel.

FIGS. 4A and 4B are enlarged views showing a portion encircled in IV inFIG. 1, and specifically, FIG. 4A is an enlarged plan view showing theportion encircled in IV in FIG. 1 and FIG. 4B is an enlarged perspectiveview thereof.

FIG. 5 is a plan view showing a step of manufacturing the liquid crystaldisplay panel 1 in accordance with a preferred embodiment of the presentinvention.

FIG. 6 is an enlarged plan view showing an arrangement in a portionencircled in VI in FIG. 5.

FIG. 7 is a plan view showing a step of manufacturing the liquid crystaldisplay panel in accordance with a preferred embodiment of the presentinvention.

FIG. 8 is a partial plan view of a conventional substrate structure.

FIG. 9 is a schematic sectional view of a portion taken along the lineIX-IX in FIG. 8.

FIG. 10 is a schematic sectional view of a portion taken along the lineX-X in FIG. 6.

FIG. 11 is a schematic sectional view for explaining a scribing step inthe case where a thick scribe mark is formed.

FIG. 12 is a schematic sectional view of a portion taken along the lineXII-XII in FIG. 6 for showing a scribing step in a preferred embodimentof the present invention.

FIG. 13 is a partial plan view of a liquid crystal display panel inaccordance with Modified Example 1.

FIG. 14 is a schematic plan view showing in an enlarged scale a portionof a liquid crystal display panel in accordance with Modified Example 2.

FIG. 15 is a plan view showing a step of manufacturing the liquidcrystal display panel in accordance with Modified Example 2.

FIG. 16 is a schematic plan view showing an arrangement in a liquidcrystal display panel in accordance with a preferred embodiment of thepresent invention.

FIG. 17 is a plan view showing a step of manufacturing the liquidcrystal display panel in accordance with a preferred embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described belowin detail with reference to the accompanying drawings.

First Preferred Embodiment

FIG. 1 to FIG. 4 show a liquid crystal display panel 1 in accordancewith the present preferred embodiment.

The liquid crystal display panel 1 in accordance with the presentpreferred embodiment preferably includes: an active matrix substrate 10as a first substrate; a counter substrate 30 as a second substrate: anda liquid crystal layer 20 as a display medium layer provided between theactive matrix substrate 10 and the counter substrate 30. The counterelectrode 30 is not shown in FIG. 4B for the sake of explanation.

Between the active matrix substrate 10 and the counter substrate 30, asealant 40 is provided so as to surround the liquid crystal layer 20.The sealant 40 joins the active matrix substrate 10 and the countersubstrate 30 and seals the liquid crystal layer 20.

As shown in FIG. 3, the active matrix substrate 10 includes: a firstsubstrate body 11 made of glass, for example; a plurality of gate lines12 extending in parallel to each other; a plurality of source lines 13extending in parallel to each other; a plurality of thin film transistorelements (hereinafter, they may be referred to as “TFT elements”) 14; aninterlayer insulating film 15; a plurality of pixel electrodes 16substantially made of transparent conductive oxide (indium tin oxide,indium zinc oxide, or the like, for example); scribe marks 50 in atrapezoidal form in plan view formed in the peripheral portion of thefirst substrate body 11 separately from the edges of the first substratebody 11; a first rubbing film (an alignment film) 17; and a firstpolarizing plate 18 provided on the surface opposite to the surface onthe liquid crystal layer 20 side of the first substrate body 11.

The plurality of gate lines 12 are formed on the first substrate body11. The plurality of source lines 13 are formed across the gate lines 12so as to extend in parallel to each other in a direction intersectingwith the gate lines 12 (typically, intersecting at a right angle). Thegate lines 12 and the source lines 13 are preferably made of metal, suchas tungsten (W), tantalum (Ta), or the like. An insulating film (asilicon oxide film, a silicon nitride film, or the like, for example) isformed between the gate lines 12 and the source lines 13 for insulatingthem from each other.

The TFT elements 14 as switching elements, which are electricallyconnected to both the gate lines 12 and the source lines 13, areprovided in the vicinity of the intersections of the plurality of gatelines 12 and the plurality of source lines 13. The interlayer insulatingfilm 15, which is preferably made of organic resin (resin of which maincomponent is epoxy acrylate resin, urethane acrylate resin,o-diazonaphthoquinone novolac based resin, or the like), is formed onthe plurality of TFT elements 14. The resin used for the interlayerinsulating film 15 preferably has high light transmittance, lowdielectric constant, large resistivity, and high mechanical strength.

The plurality of pixel electrodes 16 arranged in a predetermined pattern(typically, arranged in matrix) and the scribe marks 50 are formed onthe interlayer insulating film 15. Through holes 15 a open to the TFTelements 14 are formed in the interlayer insulating film 15 so that thepixel electrodes 16 and the TFT elements 14 are connected electricallyto each other through the through holes 15 a. The scribe marks 50 in thepresent specification are alignment marks for aiding precise division.

In the liquid crystal display panel 1 in accordance with the presentpreferred embodiment, the film of the pixel electrodes 16 is thethinnest of all the conductive members of the electrode lines of thegate lines 12 and the source lines 13, the pixel electrodes 16, and thelike. The scribe marks 50 are formed of the same film as a conductiveoxide film, for example, an ITO film forming the pixel electrodes 16,which are the thinnest of all the conductive members.

As shown in FIG. 4, the interlayer insulating film 15 separating andinsulating the TFT elements 14 and the pixel electrodes 16 covers theentire surface of a portion on the liquid crystal layer 20 side of thefirst substrate body 11 which is located at the periphery of the liquidcrystal display panel 1 with a portion of the first substrate body 11exposed which is overlapped with a portion (a corner part, for example)of the sealant 40. The interlayer insulating film 15 functions also as agenerally-called flattening film for flattening a portion of the surfaceon the liquid crystal layer 20 side of the first substrate body 11 whichis located at the periphery of the liquid crystal display panel 1. Eachportion of both the surfaces of the first substrate body 11 includingthe surface on the liquid crystal layer 20 side which is located at theperiphery of the liquid crystal display panel 1 is formed so as to beflat and smooth.

The reason why a portion (a portion overlapped with a corner of thesealant 40, for example) of the first substrate body 11 is allowed to beexposed through the interlayer insulating film 15 is to increase theadhesiveness of the sealant 40, which is made of a material generallyexhibiting excellent adhesiveness to inorganic materials, for example, amaterial of which main component is epoxy-based thermosetting resin,ultraviolet curing resin, or the like, to the active matrix substrate40.

The counter substrate 30 includes: a second substrate body 31 made ofglass, for example; a color filter layer 32; an upper common electrode33; a second rubbing film (an alignment film) 34; and a secondpolarizing plate 35 provided on the surface on the opposite side of theliquid crystal layer 20 side of the second substrate body 31. The colorfilter layer 32 is formed on the second substrate body 31 and iscomposed of a plurality of types of filter layers different from eachother in color tone for transmitting light and a black matrix layerdividing the filter layers. The upper common electrode 33 is formed onthe color filter layer 32, and the second rubbing film 34 in contactwith the liquid crystal layer 20 is formed on the upper common electrode33. Each portion of the surfaces, including the surface on the liquidcrystal layer 20 side, of the counter substrate 30 which is located atthe periphery of the liquid crystal display panel 1 is formed so as tobe flat and smooth.

A process for manufacturing the liquid crystal display panel 1 will bedescribed next with reference to FIG. 5 to FIG. 12.

First, as shown in FIG. 5, a first mother glass 60 as a base material ofthe active matrix substrate 10 is prepared. The first mother glass 60 isa large-size glass substrate from which a plurality of active matrixsubstrates 10 can be cut out (for example, about 120 active matrixsubstrates 10 arranged in matrix of 12 rows by 10 columns). On the firstmother glass substrate 60, the gate lines 12, the source lines 13, theTFT elements 14, the pixel electrodes 16, the scribe marks 50, and thelike are formed sequentially to form plural constitutional units of theactive matrix substrates 10 connected to each other in series on thefirst mother glass 60 as the first substrate body 11.

In this active matrix substrate forming step, the scribe marks 50 arepreferably formed with the use of the same film as the film forming thepixel electrodes 16 simultaneously with the formation of the pixelelectrodes 16.

In parallel to the above step, a second mother glass 70 as a basematerial of the counter substrate 30 is prepared. The second motherglass 70 is a middle-size glass substrate smaller than the first motherglass substrate 60, from which a plurality of counter substrates 30 canbe cut out (for example, about 10 counter substrates 30 arranged in onedirection). On the second mother glass substrate 70, the color filterlayer 32, the upper common electrode 33, the second rubbing film 34, andthe like are formed sequentially to form plural constitutional units ofthe counter substrates 30 arranged in one direction simultaneously.

Thereafter, a plurality of annular sealants 40 each having an opening (aliquid crystal injection port) are formed on the first mother glass 60by, for example, screen printing. Then, the second mother glasssubstrate 70 is arranged on and joined to the sealants 40 to thusmanufacture a substrate structure (joined substrate) 80 in which pluralconstitutional units are formed in a predetermined pattern (typically inmatrix), as shown in FIG. 5.

Next, the substrate structure 80 is cut to form a strip-shaped substratestructure 81 in which a plurality of constitutional units are arrangedin one direction (hereinafter this step may be referred to as a “firstdividing step”). Specifically, first scribe lines (linear cracks) 61 aare formed in each of the active matrix substrate 10 and the countersubstrate 30 preferably by a cutter wheel with the use of the pairs ofscribe marks 50 opposed to each other as guides so as to pass throughthe centers of the slits between pairs of scribe marks 50, as shown inFIG. 5 and FIG. 6. Then, the substrate is divided along the first scribelines 61 a to form the strip-shaped substrate structure 81.

In general, in order to simplify the manufacturing process, the liquidcrystal layers 20 are formed by injecting liquid crystal to a pluralityof vacant cells arranged in a strip. After formation of the liquidcrystal layers 20, the plural constitutional units arranged in a stripare divided individually to complete a plurality of liquid crystaldisplay panels 1 (hereinafter this step may be referred to as a “seconddividing step”). Specifically, second scribe lines 61 b for dividing theplural constitutional units arranged in a strip are formed in each ofthe active matrix substrate 10 and the counter substrate 30 so as topass through the centers of the slits between the pairs of scribe marks50 opposed to each other. Hereinafter, the first scribe lines 61 a andthe second scribe lines 61 b may be called scribe lines 61 collectively.Then, the substrates are divided along the second scribe lines 61 b tothus complete the liquid crystal display panels 1. Conventionally,breakage and chipping occur in the active matrix substrate 10 and thecounter substrate 30 with high frequency in the first and seconddividing steps.

As described above, the sealant 40 exhibits high adhesiveness toinorganic members when compared with that to organic members, andaccordingly, the active matrix substrate 10 and the counter substrate 30adhere to each other strongly. On this basis, it is preferable to exposea portion of the first substrate body 11 to a portion (a corner, forexample) of the sealant 40 without forming the interlayer insulatingfilm 15 in the vicinity of the corners of the liquid crystal displaypanel, as shown in FIG. 8. If so, there are formed in the scribe lines61 a portion where the interlayer insulating film 15 is formed and aportion where the interlayer insulating film 15 is not formed.Accordingly, as shown in FIG. 9, a step 15 b is formed at the boundarybetween the portion where the interlayer insulating film 15 is formedand the portion where the interlayer insulating film 15 is not formed.

The scribe lines 61 are formed across the step 15 b, which causescomparatively large stress at the step 15 b, thereby increasing thepossibility of forming undesirable cracks and chips in the vicinity ofthe step 15 b which may cause breakage and chipping of the active matrixsubstrate 10 and the counter substrate 30. For this reason, it isdifficult to manufacture a liquid crystal display panel from theconventional substrate structure 80 at high production efficiency.

In contrast, in the present preferred embodiment, no step is formed inthe scribe lines 61 and the scribe lines 61 are flat to lower thepossibility of causing breakage and chipping of the active matrixsubstrate 10 and the counter substrate 30.

In the present preferred embodiment, as shown in FIG. 6, a portion ofthe first substrate body 11 (a portion overlapped with the corner of thesealant 40, for example) is exposed to the sealant 40 through theinterlayer insulating film 15, and the interlayer insulating film 15covers a region where the scribe lines 61 is to be formed. Accordingly,as shown in FIG. 10, the vicinity of the scribe lines 60 on the surfaceon the liquid crystal layer 20 side of the first mother glass substrate60 is flat. In detail, the interlayer insulating film 15 covers theperiphery of the surface on the liquid crystal layer 20 side of thefirst substrate body 11 of the divided liquid crystal display panel 1,and therefore, the periphery of the surface on the liquid crystal layer20 side of the first substrate body 11 is flat. Hence, in the presentpreferred embodiment, undesirable cracks are effectively prevented frombeing formed in the surface on the liquid crystal layer 20 side of theactive matrix substrate 10 in forming the scribe lines 61 in the firstmother glass substrate 60 in the first and second dividing steps. Thisenables the liquid crystal display panel 1 to be manufactured with highproduction efficiency.

Preferably, the flattening film for flattening the vicinity of thescribe lines 60 in the surface on the liquid crystal layer 20 side ofthe first mother glass substrate 60 is made of resin (more preferably,organic resin) as in the present preferred embodiment. By covering thescribe lines 61 with resin, undesirable cracks are prevented effectivelyfrom being formed in the scribing step.

In the present preferred embodiment, a portion of the surface on theliquid crystal layer 20 side of the counter substrate 30 which islocated at the periphery of the divided liquid crystal display panel 1is flat, as well. Specifically, the vicinity of the scribe lines 61 inthe surface on the liquid crystal layer 20 side of the second motherglass substrate 70 is flat. Accordingly, in the present preferredembodiment, undesirable cracks are effectively prevented from beingformed in the surface on the liquid crystal layer 20 side of the countersubstrate 30 in forming the scribe lines 61 in the second mother glasssubstrate 70 in the first and second dividing steps. This enables theliquid crystal display panel 1 to be manufactured with high productionefficiency.

The scribe marks 50 in the present preferred embodiment will bedescribed further in detail.

In the present preferred embodiment, the scribe marks 50 are not formedacross the scribe lines 61 but are formed so as to be opposed to eachother with the scribe lines 61 interposed. In other words, the scribemarks 50 are formed apart from the edge of the active matrix substrate10 of the divided liquid crystal display panel 1. For example, in thecase where the scribe marks 50 are formed across the scribe lines 61,undesirable cracks might be formed in the scribing step in the vicinityof portions where scribe marks 50 are formed, which is due to thedifference in material characteristics (hardness and the like, forexample) between the scribe marks 50 and the first mother glasssubstrate 60. In contrast, in the present preferred embodiment, thescribe marks 50 are not formed across the scribe lines 61 to suppressformation of undesirable cracks. Hence, the liquid crystal display panel1 can be manufactured with high production efficiency.

Further, in the present preferred embodiment, the scribe marks 50 arepreferably formed of the same film as the film of the pixel electrodes16 which is the thinnest of all the conductive members of the electrodelines (the gate lines 12, the source lines 13, and the like), the pixelelectrodes 16, and the like. In other words, the scribe marks 50 areformed comparatively thinly in the present preferred embodiment. Thiseffectively suppresses breakage and chipping of the counter substrate30.

For forming the scribe marks 50 in the counter substrate 30, the cutterwheel 80 presses and scans the counter substrate 30. The countersubstrate 30, which is comparatively thinner than the active matrixsubstrate 10, is deformed convexly toward the active matrix substrate 10by the pressure from the cutter wheel 80. In the case where the opposedscribe marks 50 interposing the scribe lines 61 are comparatively thick,the thus deformed counter substrate 30 may be in contact with the scribemarks 50, as shown in FIG. 11. When the counter substrate 30 is incontact with the scribe marks 50, the counter substrate 30 is pressed bythree members of the pair of scribe marks 50 and the cutter wheel 80,thereby increasing the possibility of causing breakage and chipping ofthe counter substrate 30. This might lower the production efficiency.

In contrast, in the present preferred embodiment, the scribe marks 50 isformed comparatively thinly to suppress contact of the counter substrate30 to the scribe marks 50, as shown in FIG. 12. Accordingly, formationof undesirable cracks and the like in the counter substrate 30 issuppressed, thereby enabling manufacture of the liquid crystal displaypanel 1 with high production efficiency. In view of this, it ispreferable that the scribe marks 50 on the active matrix substrate 10are thin enough not to be in contact with the counter substrate 30 inthe scribing step.

Though the scribe marks 50 are preferably formed of the same film as theconductive oxide film forming the pixel electrodes 16 in the presentpreferred embodiment, the present invention is not limited thereto andthe scribe marks 50 may be substantially formed of a metal material, forexample. To do so, the scribe marks 50 may be formed of the same film asa film forming the electrode lines of the gate lines 12 or the sourcelines 13, for example. The scribe marks 50 made of a metal material isexcellent in visibility, and therefore, more precise division can beachieved.

MODIFIED EXAMPLE 1 MODIFIED EXAMPLE OF THE FIRST PREFERRED EMBODIMENT

FIG. 13 shows a liquid crystal display panel in accordance with ModifiedExample 1.

As shown in FIG. 13, the surface on the liquid crystal layer 20 side ofthe second substrate body may be flattened in such a manner that a blackmatrix layer 32 a included in the color filter layer 32 is formed so asto cover a portion of the surface on the liquid crystal layer 20 sidethereof which is located at the periphery of the liquid crystal displaypanel. In other words, the black matrix layer 32 a may cover a portionof the second mother glass substrate 70 where the scribe lines 61 areformed.

MODIFIED EXAMPLE 2 MODIFIED EXAMPLE OF FIRST PREFERRED EMBODIMENT

FIG. 14 shows a liquid crystal display panel in accordance with ModifiedExample 2. FIG. 15 shows a manufacturing step thereof.

As shown in FIG. 14 and FIG. 15, each scribe mark 50 may be a set ofmarks having a substantially triangular shape (e.g., equilateraltriangle) in plan view.

Second Preferred Embodiment

FIG. 16 shows a liquid crystal display panel 2 in accordance with asecond preferred embodiment. FIG. 17 shows a manufacturing step thereof.

The liquid crystal display panel 2 in accordance with the secondpreferred embodiment preferably has the same features as the liquidcrystal display panel 1 in accordance with the first preferredembodiment except for the arrangement of the scribe marks 50.Hereinafter, only the arrangement of the scribe marks 50 in the secondpreferred embodiment will be described in detail. In the description ofthe second preferred embodiment, the reference numerals common to thoseof the first preferred embodiment are assigned to elements havingsubstantially the same functions for omitting detailed description.

In the liquid crystal display panel 2 in accordance with the secondpreferred embodiment, the scribe marks 50 are preferably formed to havea substantially rectangular shape in plan view of which one of the sidesthereof is aligned with an edge of the active matrix substrate 10 inplan view. In other words, as shown in FIG. 17, the scribe marks 50having a substantially rectangular shape in plan view are formed acrossthe scribe lines 61. In this case, the scribe marks 50 may be made of ametal material but preferably is made of conductive oxide (the same filmas the film of the pixel electrodes 16, for example). Scribing of thescribe marks 50 made of a metal material, which is largely different inmaterial characteristics from the glass-made first substrate body 11,readily forms undesirable cracks or the like in the vicinity of thescribe marks 50. In contrast, the scribe mark made of conductive oxidecomparatively similar in material characteristics to glass, such asindium tin oxide, indium zinc oxide, or the like effectively suppressesformation of cracks and the like in the vicinity of the scribe marks 50.Hence, the liquid crystal display panel 2 capable of being manufacturedwith high production efficiency can be attained.

In the second preferred embodiment, sides 50 a of the scribe marks 50are intersected at a right angle with the edge of the active matrixsubstrate 10 (scribe lines 61). This effectively suppresses formation ofcracks and the like in the vicinity of the scribe marks 50 when comparedwith the case, for example, where the sides 50 a of the scribe marks 50are inclined with respect to the scribe lines 61.

It is noted that the scribe marks 50 referred to in the first and secondpreferred embodiments and Modified Examples 1 and 2 are mere examplesand are not limiting of the present invention in any respect.

Hereinbefore, the preferred embodiments of the display panel inaccordance with the present invention have been described by referringto the active matrix liquid crystal display panels in first and secondpreferred embodiments and Modified Examples 1 and 2, but the displaypanel in accordance with the present invention is not limited to theactive matrix display panels. For example, the display panel may be apassive matrix display panel or a segment display panel. Further, theflattening film is not limited to the interlayer insulating film 15 andmay be another film. For example, a metal reflective film (see, JapaneseUnexamined Patent Application Publication No. 11-242215 and the like,for example) or a color filter flattening film (see, Japanese UnexaminedPatent Application Publication No. 4-60517 and the like, for example)may be used in the case of a passive matrix display panel.

Moreover, the display panel in accordance with the present invention isnot limited to the liquid crystal display panel and may be any kind ofdisplay panels, such as an inorganic electroluminescent display panel,an organic electroluminescent display panel, a field emission displaypanel, a plasma display panel, and the like. In addition, the presentinvention is applicable to various kinds of general electroniccomponents.

As described above, the display panel in accordance with variouspreferred embodiments of the present invention can be manufactured withhigh production efficiency and is, therefore, useful for mobileappliances, such as mobile phones, PDAs, and the like, televisions,electronic books, monitors, electronic posters, watches, electronicshelf labels, emergency signs, and the like.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing the scope andspirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A display panel comprising: a first substratemade of glass; a second substrate opposed to the first substrate; adisplay medium layer provided between the first substrate and the secondsubstrate; and a sealant arranged between the first substrate and thesecond substrate to surround the display medium layer, join the firstsubstrate and the second substrate, and seal the display medium layer;wherein the first substrate includes: at a side of the display mediumlayer, a plurality of marks located at a periphery of the display paneland outside of the sealant, when viewed in plan; a plurality of pixelelectrodes made of transparent conductive oxide; and an electrode linemade of a metal material; wherein the plurality of marks each include aside portion extending along a first edge of the first substrate; theplurality of marks are spaced apart from the first edge of the firstsubstrate; the plurality of marks are separated from each other and arelinearly arranged along the first edge of the first substrate, whenviewed in plan; the plurality of marks have the same shape orsubstantially the same shape when viewed in plan; and the plurality ofmarks are provided in at least one corner of the first substrate.
 2. Thedisplay panel of claim 1, wherein the display panel is anelectroluminescent display panel.
 3. The display panel of claim 1,wherein the side portion of each of the plurality of marks is parallelor substantially parallel to the first edge of the first substrate. 4.The display panel of claim 1, wherein the plurality of marks areprovided on a flat surface.
 5. The display panel of claim 4, wherein theflat surface is covered by an interlayer insulating film.
 6. The displaypanel of claim 1, further comprising an additional mark that is incontact with the first edge of the first substrate or a second edge ofthe second substrate.
 7. The display panel of claim 1, wherein theplurality of marks each have a vertex arranged so as to face a side ofat least one of the first edge of the first substrate and a second edgeof the second substrate, when viewed in plan.
 8. The display panel ofclaim 1, further comprising an additional mark having a trapezoidalshape, such that an upper base and a lower base of the additional markare parallel or substantially parallel to the first edge of the firstsubstrate or a second edge of the second substrate.
 9. The display panelof claim 1, wherein the plurality of marks are made of a metal material.10. The display panel of claim 9, wherein the plurality of marks aremade of a same metal material as that of the electrode line.
 11. Thedisplay panel of claim 1, wherein the plurality of marks are made of atransparent conductive oxide.
 12. The display panel of claim 1, furthercomprising at least one scribe mark.
 13. The display panel of claim 1,wherein the second substrate has a thickness of about 0.5 mm or less.14. A display panel comprising: a first substrate made of glass; asecond substrate opposed to the first substrate; a display medium layerprovided between the first substrate and the second substrate; and asealant arranged between the first substrate and the second substrate tosurround the display medium layer, to join the first substrate and thesecond substrate, and to seal the display medium layer; wherein thedisplay panel is an electroluminescent display panel; and the firstsubstrate includes: at a side of the display medium layer, a pluralityof marks located at a periphery of the display panel and outside of thesealant, when viewed in plan; a plurality of pixel electrodes made oftransparent conductive oxide; and an electrode line made of a metalmaterial; wherein the plurality of marks each include a side portionextending along a first edge of the first substrate; the plurality ofmarks are spaced apart from the first edge of the first substrate; theplurality of marks are separated from each other and are linearlyarranged along the first edge of the first substrate, when viewed inplan; the plurality of marks have the same shape or substantially thesame shape when viewed in plan; and the plurality of marks are providedin at least one corner of the first substrate.
 15. The display panel ofclaim 14, wherein the electroluminescent display panel is an organicelectroluminescent display panel.
 16. The display panel of claim 14,wherein the first edge of the first substrate is formed in a scribingstep of the first substrate.